Agricultural combines are large machines that harvest, thresh, separate and clean agriculturally cultivated grain. The clean grain is stored in a grain tank arranged on the combine. As a rule, the threshed-out straw is either chopped and distributed across the field over the width of the cutter head or conducted around the straw chopper and deposited on the field in a swath without being chopped in order to be able to take it up subsequently with a baler. The rest of the harvested crop that remains at the rear outlet of the grain cleaning arrangement, such as chaff and small straw particles, are distributed across the field by a chaff spreader or conducted through the straw chopper and distributed across the field. The last named solution has the advantage that no separate chaff spreader is required but it requires that the straw be conducted around the rear of the straw chopper in the swath operating mode. Examples of such combines are described by DE 100 64 356 A and DE 102 56 744 A.
In DE 100 64 356 A, a sheet metal guide plate is located underneath the rear straw outlet of an axial separating arrangement, it is connected with its lower end to the frame of the combine in joints so as to pivot about a horizontal pivot axis extending transverse to the forward direction of operation. It can pivot between a swath depositing position, in which it extends at an angle upward and towards the front and that guides the straw that was ejected from the axial separating arrangement along its rear side to the rear of the straw chopper, and a chopper position in which it extends approximately vertically and guides the straw along its forward side into the straw chopper arranged underneath the pivot axis. In both modes of operation the chaff and small straw particles are conveyed by the suction effect of the straw chopper into the straw chopper during the cleaning.
DE 102 56 744 A proposes that a straw guide element connected at joints and pivoted about a horizontal axis extending transverse to the direction of operation be arranged to pivot about the axis of rotation of an ejection drum arranged underneath the outlet of an axial separating arrangement. Accordingly, the straw can be guided into the straw chopper or conducted past its rear side onto the ground, when the straw guide element is pivoted into the corresponding position. The chaff and small straw particles are conveyed into the inlet of the straw chopper by a conveying chute.
In the case of the two arrangements described that accomplish the deflection of the harvested crop by way of pivoted, but essentially rigid and stationary guide elements, it is seen as a disadvantage for the supply of straw to the straw chopper or for the deposit of swaths to the rear of the straw chopper, that the attainable throughput is limited by the friction of the harvested crop against the guide elements. A further problem lies in the fact that the straw chopper must be arranged further to the rear on the basis of the increase in the capacity of the newer implements in current practice that lead to cleaning arrangements of increased length, which makes it more difficult to convey the straw from a separating arrangement to the straw chopper either without (DE 100 64 356 A) or by way of a single driven conveying arrangement (DE 102 56 744 A).
DE 36 44 900 A describes another combine in which a straw guide surface is provided that can be pivoted between a swath depositing position and a chopper position and is located between the rear outlet of a straw shaker and the inlet of the straw chopper, the straw guide surface can be pivoted between a swath depositing position and a chopper position. At its lower end the straw guide surface can be pivoted about a horizontal pivot axis extending transverse to the direction of operation which is connected in joints to the frame of the combine in order to pivot between the swath depositing position in which it extends at an angle upward and to the rear and conducts the straw ejected by the straw shaker onto the ground ahead of the straw chopper and a chopper position in which it extends at an angle upward and to the front and guides the straw into the straw chopper arranged to the rear of the pivot axis. In an embodiment the straw guide element is configured as a conveyor belt. In this arrangement it is seen as a disadvantage that a separate chaff spreader is required in order to distribute the chaff and small straw particles that were produced by the cleaning arrangement across the field, while the straw is deposited ahead of the straw chopper in the swath depositing mode.
U.S. Pat. No. 7,066,810 B is seen as forming a class; it describes a further combine in which a conveyor belt follows an ejection drum arranged downstream and to the rear of an axial separating arrangement. Sheet metal guide plates are attached to the back side of the conveyor belt, these form a duct extending downward in the chopper mode and conduct the straw into the straw chopper attached to the rear end of the conveyor belt, and located above and to the rear of the end of the belt, the chopper chops the straw and distributes it across the field. The remains from the cleaning of the harvested crop are distributed across the field by a chaff spreader. Moreover the sheet metal guide plates can be brought into a swath position in which they guide the straw onto the field to the rear of the straw chopper. Furthermore, a position is provided for the distribution of the remains of the harvested crop in which the sheet metal guide plate, that formed the forward wall of the duct in the chopper position, is pivoted at an angle to the rear, so that the crop that is to be chopped can move downward ahead of the straw chopper and be deposited on the ground mixed with the chaff from the chaff spreader. In place of the sheet metal guide plate the conveyor belt can also be pivoted into an approximately vertical position about the axis of rotation of its forward or its rear deflecting rolls, in which it conducts the straw onto the ground which was thrown by the ejection drum against its front side. Here the disadvantage is seen in the fact that separate chaff spreaders are required and that a multitude of moving components are necessary to attain the various operating modes.
What is needed in the art is a combine in which the straw can be conveyed away in the swath deposit mode as well as the chopper mode without any problems.